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>it_dwt</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN20821"
></A
><H2
>Name</H2
>it_dwt&nbsp;--&nbsp;discrete wavelet transform</DIV
><DIV
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><A
NAME="AEN20824"
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><H2
>Synopsis</H2
><DIV
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><P
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><A
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></A
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include &lt;it/wavelet.h&gt;
      </PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>vec it_dwt</CODE
>( vec v, it_wavelet_lifting_t const *lifting, int levels
        );</CODE
></P
><P
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></DIV
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><H2
>DESCRIPTION</H2
><P
> This function computes the <CODE
CLASS="PARAMETER"
>levels</CODE
>-level discrete wavelet transform of <CODE
CLASS="PARAMETER"
>v</CODE
> using the lifting steps described by <CODE
CLASS="PARAMETER"
>lifting</CODE
>. Currently the lifting steps for the usual 5/3 and 9/7 biorthogonal filters are predefined as "it_wavelet_lifting_53" and "it_wavelet_lifting_97", although you can provide your own lifting steps.
This transform is critically sampled, therefore the output vector of coefficients has the same size as the input vector <CODE
CLASS="PARAMETER"
>v</CODE
>.
  </P
><H2
>RETURN VALUE</H2
><P
>    The set of wavelet coefficients
   </P
><H2
>EXAMPLE</H2
><PRE
CLASS="PROGRAMLISTING"
>&#13;#include &lt;wavelet.h&gt;

...

/* analyse a signal 'v' using a 5-level 9/7 wavelet decomposition */
vec vt = it_dwt(v, it_wavelet_lifting_97, 5);

/* clear the high subband */
vec_set_between(vt, (vec_length(v) + 1) / 2, end, 0);

/* recompose the vector by inverse transform */
vec vr = it_idwt(vt, it_wavelet_lifting_97, 5);</PRE
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